Some 44 million people suffering from dementia worldwide. Three out of five people with Alzheimer's and other conditions linked to dementia are prone to wandering away from their caregiver; if they aren't found within 24 hours, up to half suffer serious injury, or even death.

Proximity Button, a small wearable button designed by the U.K.'s Mettle Studios for Proximity Care, was created for people living with dementia (and their caregivers). This simple wearable does only one thing: it warns caregivers when a person with dementia wanders out of a designated safe zone.

To activate the Proximity Button, a caregiver just pairs it with their phone. Then he or she puts the Proximity Button on a patient's shirt collar. Since this also includes a Bluetooth radio, the button stays in constant contact with the Proximity Button it; the second it loses contact, it assumes them wearer has wandered off, and sends an urgent alert to the caregivers' phone, letting them know to check on their patient. It has a range of around 65 feet, and caregivers can even track more than one person at a time using the app, useful for hospitals and other institutions which might have to look after multiple patients at once.

The design of the Proximity Button is clean and efficient, using a simple hooking mechanism to loop around the collar, while a magnet secures it in place. In appearance, it almost looks like a clothing store's anti-theft tag. "We didn’t want anything to look too explicitly medical, we wanted it to be a bit more towards the agnostic tech end," Mettle Studio creative director Alex Bone told Designweek. "That’s why it’s more plain, and we wanted to have all the places and weight on the inside, to make it less noticeable."

Although the Proximity Button is primarily aimed at people suffering from dementia, it could also benefit people with autism and their caregivers. As Proximity Care notes, almost half of all autistic children tend to wander, and the consequences can be frightful. "Terrifyingly, from 2009-2011, accidental drowning accounted for 91% of U.S. deaths reported in children [with an autistic disorder] aged 14 and younger due to wandering." And 77% of those children were being watched by their parents when they died.

Most wearables have a reputation for being a little frivolous, but with statistics like these, it's hard to argue that with the Proximity Button. This wearable could literally save lives. The Proximity Button and its beacon system will be available for purchase in November this year, at a still unknown price. You can sign up to be alerted when they go on sale here.

Update: A previous version of this article misstated how the Proximity Button worked. We have clarified our explanation.